Near-field antenna testing using the Hewlett Packard 8510 automated network analyzer

Near-field antenna measurements were made using a Hewlett-Packard 8510 automated network analyzer. This system features measurement sensitivity better than -90 dBm, at measurement speeds of one data point per millisecond in the fast data acquisition mode. The system was configured using external, even harmonic mixers and a fiber optic distributed local oscillator signal. Additionally, the time domain capability of the HP8510, made it possible to generate far-field diagnostic results immediately after data acquisition without the use of an external computer

Discovery of kHz Fluctuations in Centaurus X-3: Evidence for Photon Bubble Oscillations (PBO) and Turbulence in a High Mass X-ray Binary Pulsar

We report the discovery of kHz fluctuations, including quasi-periodic oscillations (QPO) at ~330 Hz and ~760 Hz and a broadband kHz continuum in the power density spectrum of the high mass X-ray binary pulsar Centaurus X-3. These observations of Cen X-3 were carried out with the Rossi X-ray Timing Explorer (RXTE). The fluctuation spectrum is flat from mHz to a few Hz, then steepens to $f^{-2}$ behavior between a few Hz and ~100 Hz. Above a hundred Hz, the spectrum shows the QPO features, plus a flat continuum extending to ~1200 Hz and then falling out to ~1800 Hz. These results, which required the co-adding three days of observations of Cen X-3, are at least as fast as the fastest known variations in X-ray emission from an accreting compact object (kHz QPO in LMXB sources) and probably faster since extension to ~1800 Hz is indicated by the most likely parameterization of the data. Multi-dimensional radiation hydrodynamics simulations of optically thick plasma flow onto the magnetic poles of an accreting neutron star show that the fluctuations at frequencies above 100 Hz are consistent with photon bubble turbulence and oscillations (PBO) previously predicted to be observable in this source. For a polar cap opening angle of 0.25 radians, we show that the spectral form above 100 Hz is reproduced by the simulations, including the frequencies of the QPO and the relative power in the QPO and the kHz continuum. This has resulted in the first model-dependent measurement of the polar cap size of an X-ray pulsar.Comment: received ApJ: April 1, 1999 accepted ApJ: September 1, 199

The Effects of Chromium on Cellular Viability and Chromium Tolerant Gene Expression within Synechococcus sp. IU 625

Heavy metal contamination in the environment is always a big concern. Many microorganisms have developed metal tolerant /resistant mechanisms to survive in such environment. Cyanobacteria Synechococcus sp. IU 625 (S IU 625) formerly known as Anacystis nidulans have been used an indicator for studying many EPA targeted heavy metals such as Zn+2, Cu+2, Hg+2. This microorganism has been reported to have resistant mechanisms to mercury and zinc. In this study, in silico analysis was used to determine the pANL plasmid-mediated chromium resistant genes of Synechococcus sp. IU 625. DOOR and STRING were used to determine the operons and identity potential transcription factors. PCR primers were designed to amplify each gene within the proposed operon. Sequencing revealed high homology to S. elongatus PCC 7942 conservation among the Synechococcus genus. To monitor gene expression, S. IU 625 cultures were supplemented with increasing concentrations of chromium and isolated on hours 0, 8, 24, and 48. Samples were subject to RT-PCR and q-PCR to quantify the proposed chromium resistance operon and transcription regulators in the presences and absence of chromium. Results showed that all genes encoding the srpCDE operon are co-expressed in high concentrations of chromium. These also, a chromosomal transcription regulator showed increased co-expression with the operon. Furthermore, the pANL plasmid, in which the operon is located, increased in number as an adaptive response to chromium stress

My Relationship with Frank Siebert

The next essay was written by Richard Garrett, who created the Penobscot Primer Project, a continuing exhibit at the Hudson Museum, University of Maine. Garrett lives in Wellington, Maine and, since 1995, has been the Principal Investigator and Project Director of the Siebert Project, funded by the National Science Foundation

Doctor of Philosophy

dissertationThe role of telomere dysfunction, defined as telomere shortening that leads to telomere uncapping, in arterial aging and hypertension is currently unexplored. Understanding the role that telomere dysfunction plays in arterial aging could lead to novel therapies and interventions designed to blunt, stop, or even reverse the arterial dysfunction that precedes cardiovascular diseases. Likewise, understanding the role that arterial telomere dysfunction plays in the pathogenesis of hypertension could ultimately produce therapies and interventions that treat or reverse high arterial blood pressure. To gain insight into the role of telomere dysfunction in arterial aging and hypertension, we first determined the association between telomere dysfunction, cellular senescence, and inflammation in aging and hypertension in human arteries. Next, we determined if arterial telomere uncapping, independent of telomere shortening, leads to cellular senescence and ensuing inflammation and oxidative stress, and subsequent arterial endothelial dysfunction, increased arterial blood pressure, and pulse wave velocity in a mouse model of telomere uncapping. Our findings demonstrate that arterial telomere uncapping occurs with advancing age and is associated with hypertension independent of telomere length. Furthermore, our results reveal that telomere uncapping leads to arterial dysfunction that is comparable iv to that seen in arterial aging and hypertension. We believe these studies lay the clinical and mechanistic foundation for future studies aimed at establishing the prognostic value of telomere uncapping as a biomarker for CVDs

A Swann\u27s Song in Middle-earth: An Exploration of Donald Swann\u27s The Road Goes Ever On and the Development of a System of Lyric Diction for Tolkien\u27s Constructed, Elvish Languages

Donald Swann is best known for his long-time collaboration with lyricist and singer Michael Flanders, with whom he served as composer, pianist and fellow singer. He composed many other serious works beyond the Flanders and Swann collaboration, including song cycles, operas, masses and other choral repertoire. This study explores one example of Swann’s classical repertory: The Road Goes Ever On: A Song Cycle, a collection of nine musical settings of texts by J. R. R. Tolkien, author of The Lord of the Rings. Beginning with biographical and stylistic synopses of both the composer and the poet, subsequent chapters include: an historical overview of the cycle’s composition, publication, and reception; an examination of Tolkien’s Elvish languages of Quenya and Sindarin and the proposal of systems of lyric diction for each; and interpretive performance guides for each of the songs, emphasizing the relationship between music and text. Appendices follow with permissions letters, documents of special interest, and poetic texts too lengthy for inclusion in the main body of the document